GTEs produce power by extracting energy from a flow of hot gas produced by combustion of fuel in a stream of compressed air. In general, turbine engines have an upstream air compressor coupled to a downstream turbine with a combustion chamber (“combustor”) in between. Energy is released when a mixture of compressed air and fuel is burned in the combustor. The resulting hot gases are directed over blades of the turbine to spin the turbine and produce mechanical power.
Turbine blades and other components of GTEs are subject to high temperatures and high local stresses during operation. Components which undergo these high temperatures and stresses may be subject to mechanical failure, either from component breakage due to a reduced cross section of the component as a result of plastic deformation, or rupture where cracks initiate and propagate until the component is broken. For turbine blades, high local stresses may contribute to platform cracks and failures.
U.S. Patent Application Publication No. 2010/0232975 (“the '975 publication”) describes a turbine blade assembly including a root connected to a platform, and an airfoil extending upwards from the platform. The '975 publication notes that the platform may experience stresses from rotation of the turbine blade assembly, and may fail due to plastic deformation caused by a combination of heat and stress. Accordingly, the turbine blade assembly of the '975 publication includes a number of ribs that are designed to increase the stiffness of the blade platform. Each rib, which can taper along the turbine blade root, extends outwardly towards a lateral edge of the platform.